The polygalactomannans are polysaccharides composed principally of galactose and mannose units and are usually found in the endosperm of leguminous seeds, such as guar, locust bean, honey locust, flame tree, and the like. Guar flour, for example, is composed mostly of a galactomannan which is essentially a straight chain mannan with single membered galactose branches. The mannose units are linked in a 1-4-.beta.-glycosidic linkage and the galatose branching takes place by means of a 1-6 linkage on alternate mannose units. The ratio of galactose to mannose units in the guar polymer is, therefore, one to two. Guar gum has a molecular weight of about 220,000.
Locust bean gum is also a polygalactomannan gum of similar molecular structure in which the ratio of glactose to mannose is one to four. Guar and locust bean gum are the preferred sources of the polygalactomannans, principally because of the commercial availability thereof.
Polygalactomannan gums swell readily in cold water and can be dissolved in hot water to yield solutions which characteristically have a high viscosity even at a concentration of 1-1.5 percent. Guar gum and locust bean gum as supplied commercially usually have a viscosity (at 1% concentration) of around 1000 and 4000 centipoises at 25.degree. C using a Brookfield Viscometer Model LVF, spindle No. 2 at 6 rpm. For example, it is desirable that a gum which functions as a protective colloid or gelling agent in oil well drilling mud compositions and oil well fracturing compositions exhibit a degree of solution stability and heat stability under operating conditions.
Further, solutions of ordinary hydrocolloid gums are not sufficiently stable under variable conditions of pH and temperature or not sufficiently stable in the presence of polyvalent metal ions to qualify for general application in the textile industry for sizing, printing and finishing operations, or in the paper industry as sizing and coating agents. Also, ordinary hydrocolloid gums are susceptible to bacterial degradation.
Accordingly, it is a main object of the present invention to provide hydrocolloid gums having improved properties for applications in petroleum, textile, printing and paper industries.
It is another object of the present invention to provide guar gum and locust bean gum compositions containing quaternary ammonium ether substituents.
It is a further object of the present invention to provide cationic guar gum and locust bean gum compositions which are superior in solution stability and heat stability and are bacteriostatic in comparison with unmodified guar gum and locust bean gum.
Other objects and advantages shall become apparent from the following description and examples.